Did you know water makes up about 60 percent of our total body composition, depending on our age? It plays a role in all our bodily functions, from the power of our muscles to the stability of our bones to the longevity of our organs. That’s why it’s vital for all humans, and for athletes in particular, to drink up so we can perform at our peak and keep pushing mile after mile. But the question that always comes up when it comes to H2O: How much water do you really need each day?
Turns out, the tried-and-true eight 8-ounce glasses per day rule might not be as universal as we’ve been led to believe. So we dove into the latest (still emerging) research and spoke with two sports-savvy dietitians for the dish about how much water to drink to optimize your performance—without going overboard.
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How much water do you need each day?
Since we all come in different shapes and sizes, perform various levels of physical activity throughout the day and week, and get exposed to different environmental elements, how much water you really need won’t fit a universal recommendation, explains Angie Asche, M.S., R.D., C.S.S.D., a Lincoln, Nebraska-based dietitian, founder of Eleat Sports Nutrition, and author of Fuel Your Body.
“There is no single fluid-intake recommendation that will work for everyone. That said, the dietary reference intake (DRI) identifies the adequate intake for water as 3.7 liters per day for men (16 cups) and 2.7 liters per day for women (12 cups),” Asche says.
Keep in mind, not all of this water intake has to come from water itself.
“This could come from any fluid or food consumed throughout the day that also provides hydration, such as fruits and vegetables, yogurt, soups, or fruit juices,” Asche says. So even that prerun banana (75 percent water) and postrun ice cream (60 percent water) add to the tally. Also, while some people say caffeine might dehydrate you, that coffee you sip on actually works out to be a net positive for your hydration status.
Here’s where the classic water recommendation comes into play. For the general population, many nutrition pros, including Mary Stewart, R.D., founder of Cultivate Nutrition in Dallas, recommend sipping on 64 ounces (or 8 cups) of plain water as your daily baseline, with the thought that your other beverages and foods will bridge the gap between that and the DRI of 96 or 128 ounces (or 12 to 16 cups).
Keep in mind that these recommendations are subject to change—based on emerging research, as well as your own personal needs and preferences. Many studies even point out that researchers base their results on trusting self-reported water consumption, which can vary widely from actual consumption
“An individual’s hydration status is constantly changing and many factors play a role. To tell if you might be dehydrated or on the way to becoming so, monitor your body weight before and after your workout—to see how much water you lost through sweat—and check your urine color first thing in the morning. The goal is to maintain a light yellow color,” Stewart says. “You definitely want to take action when you start to feel thirsty. However, don’t always wait until you get to that point as your body may already be dehydrated.”
When should I drink water to fuel my workout?
Even mild dehydration can ruin (or at least influence) your run, science proves. Heading out the door with even 1 percent less water in your body than it needs means you’ll run with noticeably less power, endurance, and muscle strength, according to a study in The Journal of Strength and Conditioning Research.
To combat this, Asche recommends this hydration strategy:
- Drink 16 to 24 ounces of water in the hour or two before your run
- Drink 4 ounces every 15 minutes during your run
- Drink 16 ounces after your run for every pound you lost during your workout
“This will vary depending on the person and their individual sweat rates, but is a good baseline to start,” Asche says.
For longer, more intense workouts, hydration might mean more than just water, Stewart says. To replenish your H2O and electrolytes all at once, consider a sports drink that will provide additional energy via carbohydrates.
Skratch Labs Sport Hydration Drink Mix
80 calories per serving, made with all-natural ingredients and high in sodium.
GU Hydration Drink Mix
Available in individual packets or a tub.
60 calories per serving, low in sugar, high in sodium.
Osmo Nutrition – Active Hydration Optimized for Women
70 calories per serving, available in a women’s specific formulas to manage blood plasma changes during the menstrual cycle.
What happens if you don’t drink enough water—or you drink too much?
Drinking to thirst may not work for everyone, Asche admits. Changes in our environmental conditions (like altitude, humidity, cold and heat) also change hydration needs and may throw our natural sense of thirst out of whack. “Being mindful of your total water intake throughout your training as well as your individual needs will help decrease your risk of dehydration,” she says.
Fascinatingly (and kind of scary): The signs and symptoms of dehydration and overhydration may overlap.
“When experiencing hypohydration, or not enough water, you may notice a reduction in performance and increase risk of injury, impaired cognitive performance, mood changes, headaches, flushed skin, and change in bowel movements,” Stewart says. “Hyperhydration, or too much water, may lead to dizziness or lightheadedness, apathy, and possibly life-threatening exercise-associated hyponatremia (EAH), in which extracellular body water enters the cells and causes organ and tissue swelling.”
If you’re urinating more than 10 times per day or notice any of those symptoms of overhydration, dial it back—and seek medical care if you’re vomiting, feeling nauseous, overly weak or notice discoloration in the hands, feet, or lips.
If you’re peeing fewer than four times per day, it’s time to drink up—and see a doctor if your pee is almost brown in color.
What can you do to drink more water?
If you find yourself constantly parched or chronically peeing gold or dark yellow—try these hydration inspiration tips from Asche and Stewart.
- Sweeten up. If you struggle with the lack of flavor, “making the fluid more palatable will help you to consume more, especially if you have a harder time drinking fluids around the time you’re training due to a lack of appetite,” Asche says. Mix in a splash of sports drink, a flavored hydration or electrolyte powder or tablet, or a few ounces of fruit juice.
- Try an infusion. For more flavor the all-natural way, “infuse water with your favorite citrus fruits and herbs. My favorite is lemon, cucumber, and mint,” Stewart says.
- Eat your H2O. Fruits and vegetables are among the most hydrating foods. Cucumber, celery, iceberg lettuce, zucchini, watermelon, strawberries, and cauliflower are among the best foods to eat for hydration, according to the Cleveland Clinic.
- Invest in good gear. A bottle you love can really help, Asche says. Bonus points if it is see-through so you can monitor your progress and even better with a straw for easy sipping. “Look for a water bottle that holds at least 20 ounces and aim to drink at least 3 of these every day,” Stewart adds.
- Create little nudges. Stewart recommends setting an alarm in the morning, afternoon, and at night to remind yourself to finish that bottle if you haven’t already. “We all carry our phone wherever we go so why not use it to help you reach your hydration goals?”
- Set yourself up for success. Before you go to bed each night, position your water bottle next to your first morning activity, either empty as a reminder to fill it up if you prefer cold water, or already filled if room temp is fine. “This may be by your toothbrush, coffee maker, or next to the dog leash,” Stewart says. “This will serve as a reminder for you to hydrate before you start your day.”